Eric Lemmon wrote: > I am amused by APC's assertion that its device is the only unit of its kind > in a 1U rack mount. Perhaps APC hasn't heard about Pulizzi Engineering's > line of asynchronous transfer switches, such as this one: > <www.pulizzi.com/Products/2007_Catalog/2007_Catalog_Page_34.pdf>
APC's heads are pretty big for as cheap as their stuff is, when you look inside them, and their construction techniques. I've used a lot of APC stuff in data centers, but in the Telco Central Offices... > The Pulizzi transfer switches have been the "gold standard" in the aerospace > industry for years, and hundreds of them are in service at Cape Canaveral, > Kennedy Space Center, and Vandenberg AFB where super-critical equipment > supports both manned and unmanned space launches. We often use the term > "Pulizzi" as generic, because they are reliable and widely used. The Pulizzi (for some reason people in telco pronounce this "Poo-loo-zee") and the stuff from Server Technologies in Utah are all I see switching critical -48 VDC loads. (www.servertech.com) <http://www.servertech.com/Products/Product/tabid/125/groupid/14/productid/18/Default.aspx> Both the ServerTech and Pulizzi products are NEBS compliant, most APC stuff isn't. Try finding PCs that are sometime. That's a joy. (HP makes them.) > If there is any possibility that the two incoming power sources may not be > exactly in phase with each other- as when one source may be an engine-driven > generator- a transfer switch that can handle asynchronous sources must be > used. The Pulizzi switch in the link above is such a device, and it is not > cheap! Definitely not cheap! Neither are the ServerTech devices... Nate WY0X
